Ribkin answers:

That’s how all sports betting works, it’s called the vigorish (or vig) or juice. It’s how sportsbooks make money. Live or online.

For example, when you see Powerhouse University vs. Barely there division I College, it’s inherent that the big powerhouse will always win straight up (though some examples are contrary, though rare). Heavy favorites will always have a low payout per dollar risked. And heavy dogs will always have a high payout per dollar risked. So if you bet that same $10 on the dog, you might get a $15 payout plus your original bet amount, for a return of $25.

When you have pointspread betting, the payouts are a little more close to even. Sometimes it is even. But mostly, you are risking $11 to win $10. Or whatever is relative. This is usually denoted by the “-110″ mark. Sometimes lines makers will adjust payouts to even or -105 to sway betting in the other direction.

I know it might seem to be a lot to digest, but I hope you get the gist. You can check http://dagus-statistics.com/sportsbetting101.htm for a better perspective on how sportsbooks calculate their payouts. Also check http://dagus-statistics.com/reviews for a list of reliable online sportsbooks that I recommend. With any other site, you risk getting scammed. Hope this helps.